Electromagnetic Field Analysis and Modeling of a Relative Position Detection Sensor for High Speed Maglev Trains

Abstract

The long stator track for high speed maglev trains has a tooth-slot structure. The sensor obtains precise relative position information for the traction system by detecting the long stator tooth-slot structure based on nondestructive detection technology. The magnetic field modeling of the sensor is a typical three-dimensional (3-D) electromagnetic problem with complex boundary conditions, and is studied semi-analytically in this paper. A second-order vector potential (SOVP) is introduced to simplify the vector field problem to a scalar field one, the solution of which can be expressed in terms of series expansions according to Multipole Theory (MT) and the New Equivalent Source (NES) method. The coefficients of the expansions are determined by the least squares method based on the boundary conditions. Then, the solution is compared to the simulation result through Finite Element Analysis (FEA). The comparison results show that the semi-analytical solution agrees approximately with the numerical solution. Finally, based on electromagnetic modeling, a difference coil structure is designed to improve the sensitivity and accuracy of the sensor.

Research on Decoupling Problem of Suspension Gap and Location of Relative Position Sensor in High Speed Maglev Train

“…Normally, the standard distance between the sensor probe and the stator plane is 10mm. As the sensor moves in the horizontal direction under the condition of constant speed, due to the periodicity of the long stator cogging, the inductance of the coil in the probe also changes periodically [5].…”

“…where x t is the position of the tooth, and x s is the position of the slot. Reference [5] shows as the position changes, the demodulated voltage signal produces a periodic change with the long stator, which represents the position signal. The two resonant coils are symmetrical, forming a group and the width is just equal to the cogging structure.…”

“…As the sensor is kind of electronic equipment, it is easy to be affected by electromagnetic field interference. As mentioned in [5], the sensor adopts the design of ''8'' word difference coils to reduce EMI, shown in Figure 2. This paper focuses on the influence of suspension gap.…”

Orientation Measurement Based on Magnetic Inductance by the Extended Distributed Multi-Pole Model

“…An ultrasound and radar device can be utilized to monitor wide areas with high accuracy, but it is bulky and cannot be used with obstacles along the optical path [ 6 ]. Magnetic induction sensors have been utilized in numerous applications such as position, orientation measurement and path tracking [ 7 – 10 ]. They are compact in size, easy to operate and capable of providing high sensitivity without mechanical contact, making them therefore suitable for small and precise measurement systems, for instance, assisting intubation procedures for medical usage and narrow pipe inspection where the space is limited and orientation should be measured and controlled.…”

An adaptive distributed dipole model for enhanced dynamic inversion in magnetic field and induction sensor

“…An ultrasound and radar can be utilized to monitor wide area with high accuracy but is bulky and cannot be used with obstacle along the optical path [27]. Magnetic sensors have been utilized in numerous applications such as motion, orientation sensing and path tracking [28][29][30][31]. It is compact in size, easy at operation and capable of providing high sensitivity without mechanical contact.…”